The present invention relates to a pneumatic tire, more particularly to a geometrical arrangement of a wavy circumferential groove and axial grooves provided in the tread portion.
In general, a pneumatic tire is provided in the tread portion with circumferential grooves and axial grooves in order to improve the wet-grip performance. In many cases, axial grooves designed for a pneumatic tire suitable for high speed running are inclined to one circumferential direction, forming a unidirectional tread pattern, in order to promote the removal of water from the ground contacting patch. Further, in order to smoothen the flow of water from the circumferential groove(s) disposed in a tread central region to the inclined axial grooves, the axial grooves are connected with the circumferential groove at relatively small intersecting angles. Therefore, the tread element such as block formed between the axial groove and the circumferential groove is provided with an acute-angled corner. The acute-angled corner is very liable to deform during running due to the relatively low rigidity. As a result, there arise problems of uneven wear of the tread portion starting from the acute-angled corners, and decrease in the cornering power which results in a deterioration of the steering stability.